Manufacturers are continuously implementing new production techniques and build philosophies in efforts to reduce production cycle time and cost. Particularly for manufacturers of large-scale assemblies such as commercial aircraft, minor improvements to the production process can lead to appreciable reductions in production time and cost. One approach to reducing production cycle time and cost is to reduce the amount of labor required at final assembly. In this approach, instead of receiving a multitude of individual components and partially-completed subassemblies from a variety of different subcontractors for final assembly, large-scale manufacturers may assign to subcontractors a larger share of the production process by requesting that subcontractors provide subassemblies in a more completed state. In furtherance of this approach, large-scale manufacturers may request that the subcontractors deliver the subassemblies in a pre-painted condition.
At final assembly, mechanical fasteners such as bolts and screws may be employed to assemble the various subassemblies. Certain fasteners such as those that are exposed to the aircraft exterior must also be available at final assembly in a pre-painted condition. The heads of such fasteners may be pre-painted to match the pre-painted subassemblies. Considering the large quantity of subassemblies that make up a commercial aircraft and the overall size of such aircraft, the quantity of fasteners that must be provided in a pre-painted condition may be relatively large.
The success of the above-described build philosophy is dependent at least in part upon the availability of qualified subcontractors to perform the painting operations in a manner that is consistent with the manufacturer's quality and timeliness requirements. In this regard, the ability to achieve a reduction in production cycle time is dependent upon the ability of the subcontractor to deliver the subassembly on schedule. The ability of the subcontractor to meet quality requirements may be dependent upon the subcontractor's access to appropriate equipment and the availability of skilled technicians.
Such equipment and technicians may be necessary to meet specific requirements regarding the preparation, priming and application of intermediate and topcoat paint layers to the fasteners heads. For example, paint and other coating materials for aircraft are typically applied with precise control of film thicknesses. Difficulties in meeting film thickness requirements can occur as a result of inconsistencies during manual application of paint. Furthermore, inappropriate temperature and humidity levels during application of the paint and during curing of the paint can result in inconsistencies in adhesion and appearance (e.g., runs, wrinkles) of the painted fastener heads.
As a result of such stringent requirements, the number of subcontractors that are qualified to provide painting services may be limited. The limited number of qualified subcontractors may impact the ability to provide the large quantity of pre-painted fasteners on schedule. Difficulties in meeting schedule may be exacerbated by subcontractors that are qualified but are located remotely from the manufacturer such as in out-of-state locations. Furthermore, the remote location of such qualified subcontractors may limit the ability to procure pre-painted fasteners on an emergent need basis at final assembly. Such emergent need may occur as a result of part shortages on the production line.
Although the erection by the manufacturer of an on-site painting facility and curing oven may eliminate problems associated with the limited availability of qualified subcontractors, the construction of such a facility would defeat the goal of shifting a larger share of the production process to the subcontractors. Furthermore, the construction, operation and maintenance of an on-site painting facility and a curing oven having the requisite temperature and humidity control capabilities may be prohibitively expensive.
As can be seen, there exists a need in the art for a painting apparatus that provides an environment wherein large quantities of components such as mechanical fasteners can be painted with precise control of temperature and humidity. Furthermore, there exists a need in the art for a painting apparatus that facilitates the application of paint to fastener heads at a desired film thickness and on an automated basis without the need for skilled labor. Additionally, there exists a need in the art for a painting apparatus that allows for the painting of fastener heads on an emergent need basis. Finally, it is desirable that such painting apparatus is simple in construction and low in cost.